[README] Added instructions on turning on push notifications

@@ -224,3 +224,9 @@ As with everything else, if you have additions, fixes or updates, you are encour

#### Usage

Copy the aliases from `git-aliases` that you want to use into `~/.gitconfig`

###Push Notifications

Gitlab does not natively implement push notifications on repositories. You can set your preferences on what you'd like to be notified about following [these docs](https://docs.gitlab.com/ce/workflow/notifications.html) but you'll find "push" is not included.

To be included on push notifications, the project owner needs to specifically enable it and add your e-mail to the list. This can be done via https://xgitlab.cels.anl.gov/<path-to-repo>/services/emails_on_push/edit by anyone with admin rights on the project. If you do not have those rights, ask the project owner to do so for you.